1. Field of the Invention
The present invention relates to a thrust bearing component such as a bearing washer of a thrust rolling bearing or a thrust sliding bearing, and a bearing washer of a thrust receiving mechanism.
2. Description of the Background Art
A high mechanical property and high processing accuracy are required for a bearing washer of a thrust rolling bearing or a thrust sliding bearing, and a bearing washer of a thrust receiving mechanism (referred to as the “thrust bearing component” collectively hereinafter). Therefore, when the thrust bearing component is manufactured, it is essential to select an appropriate starting material and an optimal processing method appropriate for the material.
For example, a manufacturing method of a synchronizer ring whose structure is similar to that of the thrust bearing component is disclosed in Japanese Unexamined Patent Publication No. 11-223225. The manufacturing method of the synchronizer ring disclosed in the above document will be described with reference to FIG. 6.
First, the synchronizer ring disclosed in the above document uses a steel plate provided by hot rolling a carbon steel containing 0.6 wt % to 1.2 wt % of carbon (C), 0.1 wt % to 0.9 wt % of manganese (Mn), 0.3 wt % to 1.0 wt % of chrome (Cr), and 0.01 wt % to 0.15 wt % of silicon, as a starting material.
Thus, it is disclosed that the synchronizer ring is manufactured through a step of forming the above starting material into a predetermined shape by a pressing process, a step of providing a predetermined dimension by a machining process such as a turning process, a step of providing predetermined hardness by a heat treatment including quenching and tempering, and a step of smoothing the surface by a grinding process as a finishing process.
Recently, the environment in which the thrust bearing is used has become increasingly harsh, and accordingly it is required that the mechanical property of the thrust bearing washer is to be further improved. Meanwhile, as price reduction of the thrust bearing is required, the manufacturing process needs to be simplified without changing its quality.